Daryl,
I think any Royal paradox with bores under .740 and chokes around .690 with visible rifling is a steal at 10k. The cosmetic items can be taken care of or not and the gun is going to shoot. However, with the Holland paradox guns after 1903 or so you just can't be sure of what the regulation load was and some adjusting may be necessary.
The first volume of Roger Lake's book on rifled choke guns and the Holland paradox in particular will be available by September. Many years researched it is going to be a must have and good read.